OTD 15.8 August 15th Traditional Cache

OTD - 15:8 

Perhaps you want a smiley for every day of the year or maybe a birthday smiley. For whatever reason these 12 mini monthly power trails are here to be found. Most are easily located, with an occasional sneaky one in the mix, sat lock can be difficult in some areas.

Here are some facts for this day. You are welcome to log your interesting, quirky or fun fact/s with your log.

On This Day - August 15th 1985

The opal is made the state gemstone of South Australia. 

Opal is a precious stone which shows a variety of iridescent colours from reds, pinks and purples to yellows, greens and blues. The brilliant colours are produced by the diffraction of light through microscopic spheres within the opal which split the white light into all the colours of the spectrum. Along with diamond, emerald, ruby and sapphire, opal is one of the most valuable of gemstones. 

Opal was first discovered in Australia in 1849 near Angaston, South Australia, by German geologist Johannes Menge. Australia now produces around 97% of the world's opal. It is mined mainly in the Quilpie-Yowah region of western Queensland and Lightning Ridge in north-west New South Wales, as well as significant fields in South Australia. The fields at Coober Pedy, Mintabie and Andamooka in the central north of the state produce around 80% of the Earth's total production. Because of South Australia's rich opal fields, the opal was adopted as the state gemstone on 25 August 1985. It is also Australia's national gemstone.